For the ice cream:
Split the vanilla bean lengthwise. Scrape out the seeds. Put the seeds, pod halves, milk cream and 1/4 cup of the brown sugar in a heavy-bottomed medium saucepan. Bring just to the simmering point over low heat.
In the meantime, combine the remaining 3/4 cup brown sugar, egg yolks and vanilla extract in a large bowl and whisk until just blended. While gently whisking the yolks, drizzle the hot cream mixture into them so that they are gradually warmed up. Return everything to the saucepan and cook while stirring with a wooden spoon. Make sure that you are constantly scraping the spoon across the bottom of the pan so the custard does not scorch. The custard is done when it has thickened slightly and can evenly coat the back of the spoon. Do not let it come to a boil. Strain the custard through a fine sieve. Press our all the liquid in the vanilla beans and nestle the container holding the custard into a large bowl of ice. Let cool, stirring occasionally.
Transfer the custard to an ice cream machine and freeze according to the manufacturer's instructions. Put the finished ice cream in a storage container and freeze until firm.
For the fluff:
In a small saucepan fitted with a candy thermometer, bring the water, corn syrup, 3/4 cup sugar and vanilla bean to 246 degrees F. In the meantime, in a completely clean, dry mixing bowl of an electric mixer fitted with the whisk attachment, whip the egg whites, salt and cream of tartar until creamy and foamy, about 2 minutes. Still whisking, sprinkle in the remaining 1 tablespoon of sugar and continue to whisk until the whites hold very soft peaks, about 2 minutes. While mixing on slow speed, carefully drizzle in the hot syrup. Turn the mixer to high and whisk until thick, fluffy and just warm, about 7 minutes. Turn the mixer to low and whisk in the vanilla seeds.
For the Butterscotch Sauce:
Bring sugar, butter and vanilla bean to a boil in a medium saucepan over high heat, whisking until combined. Remove pan from the heat. Add the Scotch, return the pan to the heat and cook for 1 minute. Remove from the heat and whisk in the salt and warm cream until smooth.
For the Homemade Fudge Sauce:
Bring cream, corn syrup, sugar, cocoa, salt, and half of chocolate to a boil in a 1 to 1 1/2-quart heavy saucepan over moderate heat, stirring, until chocolate is melted. Reduce heat and cook at a low boil, stirring occasionally, 5 minutes, then remove from heat. Add butter, vanilla, and remaining chocolate and stir until smooth. Serve warm.
Put a couple of scoops of ice cream into each of 4 sundae dishes. Top with fluff and sauces. Garnish with nuts and cherry compote.
In a saucepan combine sugar, cherries, and 1/2 cup water. Bring to s a simmer and cook until cherries start to breakdown, about 6 minutes. Remove the cherries with a slotted spoon; reserve. Simmer the cooking liquid until reduced and syrupy. Remove from the heat, add the Kirsch and ignite with a long kitchen match until flames subside. Return the cherries to the pan and heat briefly. Serve warm or at room temperature.